My Crack destruction/build log

  • Thread starter Thread starter ramicio
  • Start date Start date
R

ramicio

Guest
I bought a Crack off ebay some time ago, pre-built.  It came with AΞON output capacitors.  I've since replaced the RCAs with Neutrik ones and the headphone jack with a Neutrik latching jawn.  The octal tube socket just plain sucks and the signal started becoming intermittent, so I took the amp out of commission and I am going to do a whole slew of things to it.

  • I ordered new tube sockets.  They are the teflon composite type from Parts Connexion.  They have a silver-plated crown springs inside the contacts made of beryllium copper.
  • The capacitors came dangling.  I just used packing tape to keep them held up.  It works and can't easily be seen because it's clear.  It's not ideal so I designed some brackets in SketchUp and are having them made at shapeways for $3.96 apiece.  They made specifically for my capacitors, and you can see the slots for the zip tie.  Click this sentence to visit the site and maybe purchase them.  I don't get anything for it.  I designed them and put them up for everybody.
  • The headphone jack is crooked and could use some mounting work.  I am going to look for a machinist to just nip into the top plate a tiny bit to the shape of the jack's flange so it absolutely will not move.
  • I am replacing all hardware with torx hardware.  I haven't found a place where I can get all the same alloy for all of the sizes I need and inexpensive.  McMaster-Carr has them all for cheap, but in different alloys.  Aaron's has any size you can imagine and in whatever alloy you want, but small quantities are expensive.  I would maybe go for larger quantities if people would go in on a buy (hint hint).  Fastenal doesn't really have anything, anymore.
  • I am going to have the top plate and transformer end bell powder coated.
  • I am looking to add in an audio spectrum analyzer circuit I bought some time ago.  I would like it to be after the volume control.  Will there be any impedance problems?
  • I am looking to add a timed relay circuit that won't connect the headphone output at power on until a set amount of time.
  • The Speedball upgrade will be done.  What hardware does that kit use?  If I have excess quantities from the bulk I order for the Crack itself it would be nice to have these used for mounting the Speedball.
  • I am thinking about solid silver wire with cloth insulation, and not with PVC or teflon innards.  Does anyone know of a place that sells a decent selection of sizes and colors (red, white, and black)?  I found a place in the UK, but I would prefer somewhere in North America.

So far I'm impressed with the amp.  I didn't think the sound would change that much from the on-board amp on my STX card.  Naysayers obviously don't understand that impedance is only measured at one frequency point and high-impedance headphones like my HD-650s are quite demanding of power for bass.  You need a healthy reserve of power to drive low frequencies.

When I got it:


After I fiddled with it:


More updates to come.
 
I love those capacitor brackets. Can you tell me exactly how I can purchase them.

Thanks in advance.

Bernie.
 
I'm a big fan of bending the tube pins out in that way.  Some of them get so crowded it opens up the opportunity that they might short together.  Worse yet, you could bridge two pins when taking voltage measurements.
 
I think it's cool that Tim is doing this in such a precise way, having parts CNC'd and 3D printed. It's inspiring me to put our little CNC mill in the lab to work on some projects beyond engraving tape reel flanges. Today I'm updating the wood fired Pentium III we have been using to run it for the past few years to something a little more reliable.
 
You're pretty brave to use stranded wire, it's pretty tough to build with (Be sure to trim off any little wire fingers/hairs that aren't soldered down).
 
I initially wired FPIII with a teflon insulated, stranded STP.  Tinned every wire before wrapping and soldering to terminals.   It wasnt fancy wire, I just had a hair to try it.  It was a PITA but not as much as it just plain sounded like sh*t.   I ended up tearing it out and using the Belden.   Count your blessings, it could have been much worse ... I know.  :o

PS ... Looking Good!  Very cool.
 
Double ouch; I was just thinking teflon STP might be an improvement! If you don't mind my asking, what did you use and how long did it burn in before you threw in the towel?
 
If memory serves it was some inexpensive West Penn wire, cant recall the #.  Tinned, stranded.    I dont recall how long but I didnt leave it alone for very long. Certainly not long enough based on most recommendations for teflon burn in but the high end was a mess and I wasnt waiting on it.  I have some teflon insulated wire in the main system that sounded quite good from the start.  I can tell you that the stock Belden STP was a welcome change, immediately so I never looked back.  I never have been able to find a small diameter STP with teflon insulated solid core wire.  Im sure someone makes some but Ive never found any.
 
The Belden that Bottlehead ships with the the FPIII contains a pair of foil shielded solid conductors and a drain wire within one jacket.  What I used was of the same exact construction type with the exception of the conductors being stranded rather than solid.  If something is "off" because of the of the contruction type of wiring I used the same would be said of the Belden that they ship with the kit.    I dont spend a lot of money on wire or cable but I do believe there CAN be sonic differences that are explainable by science.  NOT the voo doo science that the wire companies try and sell though.  Maybe some things are just not completely understood as of yet.  Im open to it. 

I understand that you dont buy into much about wire and cable but you did use silver plated copper instead of just copper  ;D

BTW ... the Crack has turned out very nice.  Well done sir.
 
The FPIII's signal is wired with the shielded, paired cable, not the Crack.

Nobody has ever been able to scientifically explain or measure anything YET.  That's the problem with "us" as a species, we think we already know and understand everything there is to know and understand.  Like I said, Im open to it.  You still arent convincing me that you are a complete wire naysayer though.  Cloth insulation?  Solid silver?  Precious metal wire erotica?    ;)

Legos would definitely be unique!
 
ramicio said:
...I will repeat AGAIN that there is NOTHING science does not understand about an electrical signal.
Click to expand...
Uh huh! Arrogance is not science. Ignorance easily passes as absolute knowledge, that is, until more is learned/discovered. The only absolute in human scientific knowledge is that "We do not understand everything".  If the musical signal existed in a purely electrical state without interface or interaction with any other component, we MIGHT know most.  But there is so much interaction, reaction and interface that above mantra is, at least, entertaining. But you are certainly welcome to your own "opinions"

Cheers,
Geary
 
ramicio said:
Keep thinking these delusional thoughts and just watch the money fly out of your wallet.
Click to expand...

You can find bad wire with high capacitance, and measure its impact on the signal, this is known and measurable.

You can construct similar situations by arranging the cable to maximize inductance, and this has a measurable impact on the signal.

Teflon is awesome because it doesn't melt when you solder it, all other benefits (real or imaginary) I take as a bonus.

For some additional reading, this is one way to look at things: http://www.cardas.com/content.php?area=insights&content_id=10&pagestring=Measuring+

Here is a nice paper from the AES that goes a little more into depth, and is not driven by marketing:
http://www.apiguide.net/04actu/04musik/AES-cableInteractions.pdf

I don't get too crazy with wire, I can build out a badly designed circuit and no amount of fancy wire or fancy caps will correct the design itself.
 
You must log in or register to reply here.

Similar threads

V
Crack as preamp for class D power amp
Replies
2
Views
139
vanishingstyleofmind
V
T
Upgrades Capacitor / other
Replies
9
Views
412
Tabaia
T
hmbscott
Completed a Switched SUT Installation
Replies
2
Views
139
Ivan303
Ivan303
F
tube converter for crack headphone amp
Replies
5
Views
2K
formuladale
F
R
Moreplay screws?
Replies
2
Views
156
richanders114
R
Back
Top